Polyethers



United States Patent 2,991,313 POLYETHERS Wilhelm Bongard, Koln, and Erwin Miiller, Otto Bayer, and Manfred Theis, Leverkusen, Germany, assignors, by direct and mesne assignments, of one-half to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany, and one-half to Mobay Chemical Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Jan. 15, 1958, Ser. No. 709,003 Claims priority, application Germany Jan. 23, 1957 4Claims. (Cl. 260-613) This invention relates generally to a method of preparing polyethers and, more particularly, to a method for making polyethers especially well suited for reaction with a polyisocyanate to form a polyurethane.

' It has been proposed heretofore to produce an ether by reacting a chloromethyl compound with an alcohol. Ethers of relatively high molecular weight are prepared by such a process when the alcohol is a polyhydric alcohol and/ or the chloromethyl compound is a polychloromethyl compound. In accordance with this process, the chloromethyl compound reacts with the alcohol to form a polyether and hydrogen chloride. Organic compounds having chloromethyl groups in the allyl position with respect to a double bond between carbon atoms, such as, for example, allyl chloride or benzyl chloride, have proved to be particularly well suited for these prior art processes. The chemical reaction is not complete even when these compounds are used and, moreover, the hydrogen chloride liberated during the reaction frequently causes secondary reactions which produce compounds which bring about discoloration of the resulting ether. Such secondary reactions are particularly disadvantageous in the production of polyethers of relatively high molecular weight because separation of the desired poly ether from the undesirable reaction products is very dilficult or impossible.

It has been proposed to add an alkali, such as an aqueous sodium hydroxide solution, an alcoholic solution of potassium hydroxide, or a tertiary base, to the reaction mixture to combine With the hydrogen chloride. Such a process has the disadvantage that inorganic salts are formed in the reaction mixture and must be separated by washing which is very difiicult when polyethers of high molecular weight are produced.

It is therefore an object of this invention to provide a method for making polyethers which is devoid of the aforesaid disadvantages of the prior art processes. Another object of the invention is to provide an improved method for making polyethers of high molecular weight which are substantially free, from undesirable reaction products. Still another object of the invention is to provide a method for making polyethers from polyhydroxy compounds and polyohloromethyl compounds and for easily separating them from any undesirable side reaction products. A more specific object of the invention is to provide a method for making high molecular weight polyethers and for separating the desired product from undesirable side reaction products.

' Generally speaking, the foregoing objects and others are accomplished in accordance with this invention by providing a method wherein a polyhydroxy compound is reacted with an a,/8-unsaurated chloromethyl compound having at least two chloromethyl groups while the reactants are in admixture with an alkylene oxide. More specifically, the invention contemplates the preparation of polyethers by reacting a polyhydroxy compound with a compound containing at least two chloromethyl groups attached to a carbon atom which is attached to an unsaturated carbon atom while reacting the resulting hydrotype.

2,991,313 Patented July 4, 1961 gen chloride liberated during the chemical reaction with an alkylene oxide. The alkylene oxide acts as an acceptor for the hydrogen chloride and makes it possible to carry out the chemical reaction under substantially neutral conditions. The chloromethyl compound may an anti-unsaturated chloromethyl aliphatic or aromatic compound.

The novel hydrogen chloride acceptor provided by thisinvention may be used in the preparation of a polyether from any suitable nap-unsaturated chloromethyl organic compound and any suitable polyhydroxy compound. The hydrogen chloride formed will be absorbed by the alkylene oxide regardless of the internal structure of the organic compound with the only requirement being that the compound have at least two terminal chloromethyl groups attached to an unsaturated carbon atom. The invention thus contemplates a process in which the polyether is prepared from any suitable 0 8- unsaturated polychloromethyl compound, such as, for example, l,4-dichlorobutene, meta-xylylene chloride, para-xylylene chloride, 4,4-bis-(chloromethyl)diphenyl sulfone, 4,4-bis-(chloromethyl)diphenyl sulfide, 4,4- bis-(chloromethyl)diphenyl methane, 4,4'-bis-(chloromethyDdiphenyl dimethyl methane, 4,4-bisf(chloro methyDdiphenyl ether, and the like. It is thus apparent that the double bond may occur in either an aromatic ring or an aliphatic chain. 4,4'-bis-(chloromethyl)diphenyl ether has been found to be particularly well suited for making polyethers of high molecular weight and is therefore preferred over the other compounds of this Any suitable polyhydroxy compound may be used, but it is preferred to react polyhydric alcohol with the chloromethyl compound to form the polyether. Examples of suitable polyhydric alcohols include, for example, the dihydric alcohols, including diethylene glycol, propylene glycol, butane dihydroxy ethyl alcohol, and the trihydric alcohols, such as, for example, tn'methylol propane, glycerol and the like. Any other suitable compound having at least two aliphatically bonded hydroxyl groups, such as, for example, orthophenyIene-B-dihydroxy ethyl ether, m-phenylene-fi-dihydroxy ethyl ether, p-phenylenefi-dihydroxy ethyl ether, 4,4'-diphenyl dimethyl methanefl-dihydroxy ethyl ether and the like, may be used. A mixture of dihydric alcohols and alcohols having more than two hydroxyl groups may be used in order to produce a polyether having a predetermined amount of branching. The degree of branching in the polyether is obtained; by varying the proportion of dihydric alcohol to alcohol having more than two hydroxyl groups.

Any suitable alkylene oxide may be added to the reaction mixture containing the chloromethyl compound and polyhydroxy compound, the requirements for such oxides being that they form a halohydrin by reaction with the hydrogen chloride which can be removed from the reaction mixture by distillation. Such a process enables the separation of the desired polyether from the nude sired hydrogen chloride and the resulting halohydrin can be reconverted into the alkylene oxide, making it possible to employ a cyclic process with the reconverted alkylene oxide being directed back into the reaction mixture. The examples of suitable alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, amylene oxide, and the like.

The components of the reaction may be mixed together in any proportions depending upon the nature of the product desired. Molecular proportions of the two compounds may be used or more chloromethyl compound may be used than polyhydroxy compound. It is also possible to use more polyhydroxy compound than chloromethyl compound in the reaction mixture if a preponderance of organic radicals derived from the poly- 3 4 hydroxy compound are desired in the polyether. If an further reactions to form plastics of high molecular excess of the chloromethyl compound is used, the prodweight.

In order better to describe and further clarify the inuct will have terminal chlorine atoms, while the product vention, the following are specific embodiments thereof:

will have terminal hydroxyl groups if an excess of the polyhydroxy compound is used. Polyethers having term- 5 inal hydroxyl groups are particularly well suited for re acting with organic polyisocyanates to form rubber-like nornogeneons polynnetnanen or cellular, polyurethanes ether, about 100 grams of .trimethylol propane and about which may be used in making vehicle tlres, Sp g 200 grams of 1,2-propylene glycol are introduced into a the like. The polyether havmg terminal chlorine atoms flask equipped with a supply pipe, stirrer mechanism, may be further fended Wnn nynroxy cofnponnds thermometer and reflux condenser. Ethylene oxide is form Pnyetners Whlcn may then be used 1n prepanng passed through and the mixture is gradually heated to nsenn Polyurethane Products such as Sponges Yennnc from about 180 C. to about 200 C., so that no free tires or the like, by reaction of the polyether with an hydrogen chloride escapes The glycol chlorohydrin organ: Polylsocynnateformed distills out of the reaction mixture at an internal In one Preferred mode of Pracnclng the Invention the temperature of about 150 C. The condensation is conalkylene oxide is introduced into the reaction mixture tinned until no further glycol chlorohydrin distills Over containing the chloromethyl compound and polyhydroxy and the etherification is completed in vacuo at from compound after the mixture has been heated to an ele about 12 mm to about and from about 0 vated temperature. chlorohydrin is formed immediate- 20 to about C. A yellow viscous on is formed this 1y as reaction between the chloromethyl and polyhydroxy oil having an hydloxyl numbcl. of 211 and no kmger n prnceeds 1S lnnnedlalely f n n showing any Beilstein reaction. After the ethylene oxide the reaction mixture 1f the reaction mixture is maintamed also condensed during the distillatkm has been evaw at a temperature where the chlorohydrin will distill. It rated ofl, 241 grams of glycol chlorohydrin are obtained is preferred to operate in this way in order to insure 5 in the distillate rapid removal of the hydrogen chloride. The progress of the condensation reaction can be observed by increase in viscosity of the reaction mixture. The reaction mix ture may be heated to the elevated temperature and the vessel in which the heating is eitected may be evacuated. In any event, an alkylene oxide must be present in the reaction mixture.

Polyethers of any molecular weight greater than the molecular weight of the polyhydric alcohol and chloromethyl compound may be prepared in accordance with this invention and are contemplated. However, polyethers having a molecular weight of at least about 700 are preferred. Under the experimental conditions indicated in Ex The chemical reaction which produces the polyether ample 1, about 804 grams of 4,4-di-(chloromethyl)disubstantially free from undesirable side reaction prodphenyl ether and about 475 grams of diethylene glycol ucts may be represented by the following general equaare reacted while introducing ethylene oxide. A product tion: is obtained which has an hydroxyl number of 198.

Example 1 About 402 grams of -4,4'-di-(chloromethyl)diphenyl Example 2 Using the experimental conditions indicated in Example 1, about 134 grams .of 4,4-di-(chloromethyl)diphenyl ether and about 105 grams of trimethylol propane are reacted while introducing ethylene oxide. After the glycol chlorohydrin has been distilled off, a viscous oil remains which has an hydroxyl number of 338 and which is free from chlorine.

Example 8 Example 4 Under the experimental conditions indicated in Example 1, about 125 grams of dichlorobutene-1,4 and about 138 grams of hexanediol are reacted while introducing ethylene oxide and a viscous oil is obtained which has an hydroxyl number of 98.

Example 5 Under the conditions indicated in Example 1, the .eth-

wherein R is a divalent organic radical having an unsaturated carbon atom attached to the carbon atom of each chloromethyl group; R is a divalent aliphatic or aromatic radical; R is hydrogen or a methyl group; X

is either 0, 1, 2 or 3 --CH groups. Using 1, 4-dichlorobutene as an example of the chloromethyl compound, ethylene oxide as an example of an acceptor for the hydrogen chloride and ethylene glycol as the alcohol, the chemical reaction may be represented as follows:

ylene oxide is replaced by propylene oxide. The propyl The products obtained by the process of the invention chlorohydrin which is formed is then distilled off at about are completely free from chlorine if an excess of the 127 C., and a condensation product is obtained which polyhydroxy compound has been used. Undesired sechas the hydroxyl number indicated in Example 1. ondary reactions, for example, etherification of the Example 6 chloromethyl compounds with the glycol chlorohydrin Under the conditions indicated in Example 1, about 402 being formed, does not occur since the boiling point of the latter is below the reaction temperature. grams of P Y Y ether and about 80 The products obtainable by the process of the invengr ms of L -P PY glycol are condensed under the tion are yellow viscous oils, which can be obtained in a actiml of {ethylene OXide- A condensation Product is f l tel f e f o h l d fo -ex l tamed which has a chlorine content of 8.2 percent. be used as plasticizers or an inntial materials for lacquers. y member of the Class Of fihlofomethyl Compounds On account of their reactive terminal groups, in particuand of the class of polyhydroxy compounds disclosed as lar hydroxyl groups, they can serve as initial material for p rable herein may be substituted for the particular wherein n is an integer.

chloromethyl compound and polyhydroxy compound used in the foregoing examples. Likewise, any other suitable alkylene oxide may be substituted in the foregoing examples for the one specified.

Although the invention has been described in considerable detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for this purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as is set forth in the claims.

What is claimed is:

l. A method for making a polyether which comprises reacting a polyhydric alcohol having as its sole reactive groups, primary hydroxyl groups, said alcohol having from 3 to 19 carbon atoms with an a,/3-unsaturated chloromethyl compound having at least two chloromethyl groups and having a 4 to 17 carbon atoms while said compounds are in admixture with an alkylene oxide, selected from the group consisting of ethylene oxide, propylene oxide, bu-tylene oxide, and amylene oxide, and at a temperature whereby the resulting halohydrin is removed by distillation from the reaction mixture substantially as soon as it is formed.

2. The process of claim 1 wherein said alkylene oxide is ethylene oxide.

3. The process of claim 1 wherein said alkylene oxide is propylene oxide.

4. The process of claim 1 wherein said o p-unsaturated chloromethyl compound is 4,4'-(chloromethy-l) diphenyl ether.

References Cited in the file of this patent UNITED STATES PATENTS 2,060,715 Arvin Nov. 10, 1936 2,788,350 Lafyatis et a1. Apr. 9, 1957 FOREIGN PATENTS 456,278 Great Britain Nov. 2, 1936 OTHER REFERENCES Karrer: Organic Chemistry, 4th edition (1950), page 244.

"corrected below.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 2 99l 3l3 July 4 1961 Wilhelm Bongard et alu error appears in ihe above numbered pat- It is hereby certified that r the said Letters Patent should read as ent requiring correction and that for that portion of the formula Column 3, line 47,

H" read H(O-R -O=CH an integer line 18 Strike out "a a initial column 5 Signed and Sealed this 2nd day of January 1962.

(SEAL) littest:

ERNEST W. SWIDER Attesting Officer IDAVTDIQIJUUD Commissioner of Patents 

1. A METHOD FOR MAKING A POLYETHER WHICH COMPRISES REACTING A POLYHYDRIC ALCOHOL HAVING AS ITS SOLE REACTIVE GROUPS, PRIMARY HYDROXYL GROUPS, SAID ALCOHOL HAVING FROM 3 TO 19 CARBON ATOMS WITH AN A,B-UNSATURATED CHLOROMETHYL COMPOUND HAVING AT LEAST TWO CHLOROMETHYL GROUPS AND HAVING A 4 TO 17 CARBON ATOMS WHILE SAID COMPOUNDS ARE IN ADMIXTURE WITH AN ALKYLENE OXIDE, SELECTED FROM THE GROUP CONSISTING OF ETHYLENE OXIDE, PROPYLENE OXIDE, BUTYLENE OXIDE, AND AMYLENE OXIDE, AND AT A TEMPERATURE WHEREBY THE RESULTING HALOHYDRIN IS REMOVED BY DISTILLATION FROM THE REACTION MIXTURE SUBSTANTIALLY AS SOON AS IT IS FORMED. 